Grain graders utilize cylinders with apertures suitably sized for a particular size of grain to be sorted. The grain to be sorted is fed into a first end of the cylinder. The rotational axis of the cylinder is angled with respect to the horizontal such that as the grain is tumbled inside the cylinder it flows to the opposite second end of the cylinder. The grain of a size or configuration that fits through the apertures is sorted out of the cylinder. The balance of the grain flows out of the second end.
Grain graders typically have interchangeable cylinders for providing different sorting parameters. Such parameters often relate to an aspect of the grain such as size or maximum diameter. Modern graders require guard screens or other barriers to keep personnel away from the rotating parts. In many installations, the cylinders need to be regularly or frequently swapped for altering the sorting parameters. It is desirable to be able to access the cylinders and to interchange them as easily and as quickly as possible.
The apertures in the grain grader cylinders have a tendency to become clogged by grain not quite small enough to freely pass through the apertures. Means are typically provided for unclogging the apertures. In the early art, such means included elongate rigid wooden rollers extending across the top exterior of the cylinder. Such cylinders have been disclosed as rigidly fixed, see U.S. Pat. No. 410,377 issued to Rich, and vertically movable by the roller axle ends placed in vertical slits in mounting blocks, see U.S. Pat. No. 174,078 issued to Kurth. Additionally, rollers have been disclosed in the context of a pea grader that comprise wooden rollers covered with crepe rubber on an axle with the axle supported by a pair of links pivoting on the grader frame and extending upwardly to allow the rollers to pivot against the cylinder. See U.S. Pat. No. 1,841,299 to Rife. An inherent problem with such rollers as disclosed in the prior art is that they do not adequately address differences between different cylinders that may be used in the same grader, nor do they address the issue of inconsistencies in the roundness or existence of imperfections in a cylinder, nor did they address the modern practice of frequent cylinder exchanges. In conventional roller systems, an imperfection or distortion at one point on the exterior of a cylinder can cause a substantial portion of a roller assembly to separate from the cylinder causing significant breaches in the cleaning coverage. This is particularly a problem where there is such a frequent cylinder interchange. Moreover, the prior art rollers did not provide for nor were they capable of simple and safe separation from engagement with the cylinders. To applicants knowledge, such rigid rollers have not been utilized for cleaning grain graders for many decades.
Other means for unclogging the apertures have included elongate cylindrical brushes with the bristles extending into the apertures as the cylinder and brushes rotate to push any lodged material back into the interior of the cylinder. Such a brush is disclosed in U.S. Pat. No. 4,469,230 to Gorlitz, et al.
The current commercially accepted method of cleaning the cylinders of grain graders is by utilizing a rotating cleaner unit with elongate flexible flaps extending outwardly from a hub which extends down the length of the cylinder. The cleaner unit is rotatably driven such that the flaps slap against the cylinder to urge any lodged grain back into the cylinder. Such a system is disclosed in U.S. Pat. No. 5,605,233 to Hauch. There are significant disadvantages with this type of system some of which are disclosed in Hauch. Although Hauch attempts to provide a solution to a specific problem, the Hauch design still requires the flapper member to be powered and there will still be torque spikes due to the slapping action of the flaps. Moreover, the efficiency of these types of cleaners is not as great as desirable. Additionally, in operation such flap cleaners can contribute substantially to the noise generation of graders. These types of cleaner are also require relatively frequent maintenance.
A cleaner for a grader is needed that is more efficient in operation, that accommodates distortions and imperfections in cylinders, that accommodates frequent cylinder interchanges including cylinders of different sizes without equipment adjustment or modification, and that is low maintenance.